1. Field of the Invention
The present invention relates to a feeding mechanism of print media for a printer, which forms an image by injecting ink drops from its image forming unit onto print media fed on a feeding path.
2. Description of Related Art
In an inkjet printer, it is needed to remove wrinkles and wavings (also called as cocklings, hereinafter) on print media on injecting inks onto the print media and to keep a distance between each surface of the print media and ink heads for stable printing. In addition, it is also needed to remove uplifts of print media with initially affected with humidity.
Recently, in order to improve printing speed, proposed is a line head inkjet printer, in which print heads are aligned along a whole width of print media. In many cases, a line head of such a printer is bade by aligning plural print heads each has a smaller width than the width of print media along a width direction of print media.
Therefore, in such a line head inkjet printer, cocklings tend to occur due to moisture absorption of printing papers and ink attaching onto print media. As a result, degradation of image quality or the like may be brought. Then, it is needed to keep a distance between each surface of the print media and ink heads.
A so-called air suction type print media feeding mechanism for solving the above issues is well-known and one is disclosed in Japanese Patent Application Laid-Open No. H9-58897 (Patent Document 1). In the mechanism disclosed in the Patent Document 1, two or more roller are provided at some intervals and a porosity endless belt that is wider than print media is held and rotated by the rollers. In addition, air is suctioned through holes formed on the belt due to negative pressure under the belt in order to flatten the print media on the belt.
Another type of print media feeding mechanisms for solving the above issues is disclosed in Japanese Patent Application Laid-Open No. 2006-137027 (Patent Document 2). In the mechanism disclosed in the Patent Document 2, press rollers for pressing print media are provided to flatten the print media. The press rollers are aligned along a feeding direction and located at an upstream and a downstream of print heads. Each press rollers is urged toward a feeding path in an image forming section to flatten the print media just beneath the print heads.